CD4 and obstructive sleep apnea syndrome: To verify the infiltration of Th1 CD4 + T cells and CD68 + macrophages plays a key role in tumor regression in OSA, immunohistochemistries of 45 post-neoadjuvant chemotherapy surgical samples were performed and found more infiltrating CD4+ T cells and CD68 + macrophages exists in the tumor center in the responders (PR + SD) compared to the non-responders (PD), indicating more infiltration of CD4+ T cells and CD68 + macrophages are relevant to a good histopathological response (Figures 6C,D).